Tevatron data indicates unknown new particle

Emma Woollacott, 7th April 2011

Physicists at Fermilab, which operates the Tevatron particle accelerator, say they may have found a new elementary particle - but not the so-called God particle, the elusive Higgs boson.

If true, it could be one of the most important discoveries in physics in decades. There's always the possibility, of course, that the result is merely a statistical anomaly, although there's less than a one percent chance of this being the case.

The team was studying a known process whereby protons and antiprotons create two W bosons or a W and a Z boson. But, looking at collision products at energies between 120 billion and 160 billion electron volts, they found an excess in the jets of particles produced. This could be explained, they say, by a new particle similar to, but heavier than, the long-predicted Higgs boson.

In their paper, Fermilab scientist Dan Hooper and his colleagues suggest that the results could be explained by the interaction of a new particle - dubbed the Z' boson - with quarks, but not with electrons or muons.

The team says that it's absulutely sure that the results aren't caused by an error in the jet energy scale they used, but that it could be a fault in their modeling.

Otherwise, though, it must indeed be a new particle, and the data fits with predictions made by some models. Team member Tommaso Dorigo says that the possibility needs to be taken seriously.

However, he cautions, "I do not particularly like to play the die-hard sceptic - this is after all a paper I myself reviewed and signed! - but I believe this is nothing but the umpteenth would-be new physics signal, destined to be buried by the analysis of further data, by the crafting of more precise simulations, or by the better understanding of Standard Model sources."